1. Field of the Invention
The present invention relates generally to the detection of track anomalies in data storage libraries.
2. Background Art
Current automated libraries for tape cartridges typically include arrays of multiple storage cells housing the tape cartridges, as well as multiple media drives. Multiple automated robotic devices may be used to move tape cartridges between the various storage cells and media drives within a library.
The use of multiple robotic devices in automated tape cartridge libraries raises various problems concerning the distribution of power to such robotic devices. More particularly, robotic devices used in automated tape cartridge libraries require power for operation thereof. In prior art automated tape cartridge libraries, the movement of the robotic devices is restricted by wire cable connections used for providing such power. That is, such cabling can prevent the robotic devices from crossing paths, or from continuous movement in one direction around the library without the necessity of ultimately reversing direction.
Power cabling can be eliminated through the use of conductors, or power strips, running along tracks which support the robotic devices. Brushes on the robotic devices contact the conductors to supply power to the robotic devices. Alternatively, brushes may be part of a pickup assembly for supplying power to the robotic devices. For example, wheels may contact the conductors with brushes contacting the wheels.
One robotic device may be cut off from power, control signals and the like due to a fault in a conductor. What is needed is to restore operation of this robotic device without severely impacting operation of the library.
Operations along a track suffering some track anomaly are resumed by bridging the anomaly with a robotic device.
A method for recovering from an anomaly in a data storage library is provided. The data storage library has robotic devices traveling along a rail for accessing data storage devices. A determination is made that a first robotic device on the rail has become inoperative. A second robotic device is moved along the rail. The second robotic device has a first pickup and a second pickup spaced apart in a direction of travel along the rail. Each pickup contacts a conductor extending along the rail. The robotic device forms a current-carrying path between the first pickup and the second pickup. The second robotic device is halted at an anomaly in the conductor such that the first pickup is on one side of the anomaly and the second pickup is on the other side of the anomaly, thereby permitting current to flow around the anomaly. The first robotic device is operated with the current flowing around the anomaly.
In an embodiment of the present invention, the first pickup and the second pickup are each portions of a single, wide conducting element forming the current-carrying path. Alternatively, the pickups may include brushes. The current-carrying path is then formed through a conductor in series with the brushes.
In another embodiment of the present invention, the anomaly location is remembered. The second robotic device may be moved away from the anomaly and returned to the remembered anomaly location.
A data storage library is provided. Storage locations for holding data storage media are disposed within the library. A rail provides access to the storage locations. The rail includes a conductor. At least two robotic devices travel along the rail, each robotic device accessing storage media held in the storage locations. Each robotic device has at least one pickup drawing power from the conductor. A controller determines that a first robotic device cannot respond to commands from the controller in an affected area of the rail due to an anomaly in the conductor affecting current flow through the conductor in the affected area. A second robotic device is moved along the rail until the second device pickup spans the anomaly to permit current flow around the anomaly.
A method of compensating for an anomaly in a data storage library track is also provided. The track supports operation of a plurality of robotic devices. The anomaly prevents the flow of electrical current from reaching an affected section of the track. A robotic device is moved to the anomaly so that electrical current flows into a first pickup on the robotic device located on one side of the anomaly and out of a second pickup on the robotic device located on another side of the anomaly.
The above features, and other features and advantages of the present invention are readily apparent from the following detailed descriptions thereof when taken in connection with the accompanying drawings.